A communication device is a device provided with appropriate communication and control capabilities for enabling use thereof for communication with others devices. The communication may comprise, for example, communication of voice, electronic mail (email), text messages, data, multimedia and so on. The communication device may comprise any device facilitating sending and/or receiving communication, for example an appropriate user equipment (mobile or fixed), a mobile station and so on.
A communication device typically enables a user of the device to receive and transmit communication via a communication system. A communications system is a facility which facilitates the communication between two or more entities such as communication device, network entities and other nodes.
An appropriate access network arrangement provides a user with an access to the communications system. An access network typically operates in accordance with a given standard or with a given set of specifications which set out what the various elements of the system are permitted to do and how that should be achieved. For example, the standard or specification may define if the user, or more precisely user equipment, is provided with a circuit switched bearer or a packet switched bearer, or both. Communication protocols and/or parameters which should be used for the connection are also typically defined. For example, the manner in which communication should be implemented between the user equipment and the elements of the networks is typically based on a predefined communication protocol.
An access to a communications network may be provided by a fixed line or wireless communication interface. Communication systems providing wireless access enable at least some degree of mobility for the users thereof. More advanced mobility support can typically be added as an enhanced feature. An example of communication networks providing wireless access and mobility is a public land mobile network (PLMN), such as the second generation (2G) GSM (Global System for Mobile communications), the so called third generation (3G) GPRS (General Packet Radio Service), and/or the WCDMA (Wideband Code Division Multiple Access) or EDGE (Enhanced Data for GSM Evolution) and so forth.
The public land mobile networks (PLMN) are commonly based on cellular technology. In cellular systems, a base transceiver station (BTS) or similar access entity services mobile communication device via a wireless interface between these entities. The operation of the base station apparatus and other apparatus required for the communication can be controlled by one or several control entities. Other examples of wireless access technologies include various different wireless local area networks (WLANs) and satellite based communication systems.
The various control entities of a communication system may be interconnected. One or more gateway nodes may be provided for connecting a network used for accessing the system to other communication networks, for example to an IP (Internet Protocol) and/or other packet switched data networks. In such arrangements, a communication network provides a user with appropriate user equipment to access external networks, hosts, or services offered by specific service providers.
A mobile communication device may be configured to be compatible with different access technologies and thus capable of communication via a plurality of different access systems. For example, a mobile device may be provided with multi-radio capabilities, thus enabling access to services via a plurality of different radio access networks.
A communication device can be used for accessing various applications. An application may be configured such that although the application is activated, there are idle periods when no payload communication occurs. A plurality of different mechanisms have been developed to avoid dropping of the communication media during these idle periods. One example of these is where an application generates keep alive messages to maintain the communication media for idle communication devices for possible further needs. A keep alive message may be generated in different intervals, depending on the application. For example, a keep alive message may be sent every 20 s to a few minutes.
Sending of keep alive messages, or other dummy messages consumes power and thus reduces battery-life. The repeated signaling may also unnecessarily consume network resources. Problems in relation to power consumption by the mobile device may arise in other contexts as well. For example, a communication device may be provided with a communication media via an access system in an area where power consumption is high in that particular access system, for example due to obstacles in the radio path between the communication device and a base station or because the particular access system is suffering from high level of interference.
In accordance with an embodiment there is provided an apparatus comprising a controller configured to detect at least one predefined event in communications between a communication device and a communication system, and in response to detection of said at least one predefined event to trigger a handover of the communication device from a first access system to a second access system on the basis of the power efficiency of the second access system.
Another embodiment provides a communication device comprising a controller configured to detect at least one predefined event in relation to power consumption thereof, and in response to detection of said at least one predefined event to trigger a handover of the communication device from a first access system to a second access system.
A yet another embodiment provides a communication system comprising at least a first access system and a second access system, and a controller a controller configured to detect at least one predefined event in communications with a communication device via the first access system, and in response to detection of said at least one predefined event to trigger a handover of the communication device from the first access system to the second access system on the basis of the power consumption characteristics of the second access system.
A still further embodiment provides a method comprising monitoring for at least one predefined event in communications between a communication device and a communication system and triggering, in response to detection of said at least one event, a handover of the communication device from a first access system to a second access system on the basis of the power efficiency thereof.
A further embodiment provides a controller configured to detect at least one predefined event in communications between a mobile device and an access system, and in response to detection of said at least one predefined event to trigger a handover of the mobile device from the access system to another access system on the basis of the power efficiency of said other access system.
In a more specific embodiment the controller monitors for the state of the communications between the communication device and the communication system. The controller may monitor for at least one of a predefined pattern of events in the communications, keep alive messages, a predefined traffic pattern, a frequency of predefined events, and a power source.
The controller may change a quality of service parameter allocated to the communication device in response to the predefined event.
The controller may also trigger, in response to detection that the communications between the communications device and the communication system is reactivated, a handover of the communication device from the second access system to the first access system.
The controller may trigger a handover to an access system with a lesser demand for power than in the first access system.
The controller may trigger an intersystem handover in response to detection that the communication device has been idle for a predefined period and that at least one keep alive message has been transmitted.